03/10/2017 7:37 AM AEDT | Updated 03/10/2017 7:48 AM AEDT

Seeing Colours And Shapes When You Get A Migraine? This Is Why

An aura is a sign that a migraine is on its way.

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One of the most characteristic symptoms of a migraine is the aura.

Migraine auras are experienced by a third of people who get migraines and they come in many forms. The most common are visual, where a person might see shapes or colours, however auras can be sensory as well.

"A migraine aura is a really unusual set of symptoms," Professor Paul Rolan told HuffPost Australia.

"In migraine you get excitatory phenomena, you see lines, patterns, colours, shimmering, shapes. These are clearly excitatory and people may get disturbances of speech, disturbances of sensation or movement which is much less common. People may smell strange things.

"The most frequent type of aura is visual, however, there can be speech change, and usually the problem is ... they are unable to find the right words. It can be disturbance of smell, it can be disturbance of touch or sensation usually on one side of the body and more rarely it can be paralysis."

In typical cases, auras last 20 minutes and occur before the full scale of the headache sets in. What's strange about auras and migraines is that they serve no purpose whatsoever.

Rolan explained that pain is part of the body's defense system that attempts to shield us from injury and acts as a psychical reminder to avoid a similar situation in the future.

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On average the aura lasts 20 minutes and occurs before the worst of the headache has begun.

In this way, migraines are a bit of an anomaly as the pain associated with them doesn't have a known function. Migraines don't warn or protect our bodies from threat and the cause of them is unknown.

What researchers do know is that migraines are altered electrical activity and blood flow in the brain. The likelihood of experiencing an aura or migraine could be largely inherited, even though there isn't one single gene migraine is linked to.

"People who have migraines probably have a genetically predisposed condition to having a lower threshold than usual for the brain to spontaneously go into a pattern as if it had been injured," Rolan told HuffPost Australia.

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The function of pain is to protect from further injury, but migraine doesn't work like that.

Migraines are a very common problem for Australians. The frequency is the same in both boys and girls up until puberty. After puberty, the frequency of migraines triples in women and a staggering 15 percent women experience the headaches. Rolan says the reason for this is that estrogen can exacerbate the frequency of migraines.

There are a range of other triggers that can induce migraine in some people.These include lifestyle factors like too much or too little sleep and certain types of foods.

"Things that are known triggers for migraines are, for example, over or under sleep, offset of stress -- not onset. People don't usually get a migraine when they are stressed, but they usually get migraine when they come down from being stressed," Rolan said.

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Migraines occur after a stressful time, not during one.

While there isn't a known cure for migraines and migraine auras there are things that can be done to ease the pain and manage the symptoms. As well as being able to use drugs to ease the pain, Rolan said being aware of your triggers is an effective way to assist with the onset of a migraine or an aura.

Rolan says talking to your doctor is also a good idea if you get migraines as there are treatments available and there are things that can be done.